The Appellate Court of Illinois has held: "Differences in methamphetamine yield simply do not involve novel science; they involve personal applications of well[-]known and commonly accepted scientific procedures." People v. Wilke , 367 Ill.App.3d 130, 304 Ill.Dec. 933, 854 N.E.2d 275, 282 (2006). That court also explained: "It is undisputed in the scientific community that chemical processes exist whereby pseudoephedrine can be converted into methamphetamine.

Moreover, there was no indication on the recording that the garage contained other materials indicative of methamphetamine manufacturing. See, e.g., People v. Wilke, 367 Ill. App. 3d 130, 132 (2006) (noting that while an individual could legally possess pseudoephedrine, brillo pads, a cooler, a strainer, a clear plastic jug, some gas tanks, another gas tank with PVC piping, boxes of Miracle Grow plant food, white jugs with spray tops, bottles of Heet, and a lithium battery, they are ingredients in methamphetamine production). The only indication from the call was that there might be powder or pills located in the garage.

Other jurisdictions around the country have adopted this method, and expert witnesses are employed to apply the conversion ratio due to its case-by-case variability. See, e.g., People v. Wilke, 367 Ill.App.3d 130, 304 Ill.Dec. 933, 854 N.E.2d 275, 278 (2006) (“an agent for the United States Drug Enforcement Administration ... would testify to a mathematical formula used for determining how much methamphetamine could be produced with a given amount of precursor pseudoephedrine.”); Hill v. State, 161 S.W.3d 771, 777 (Tex.App.2005) (“[Agent from Deep East Texas Regional Narcotics Task Force] replied that by using the amounts listed on each package, he calculated a total of 5,760 milligrams of pseudoephedrine.